After the last book in the VI Warshawski series I was tempted to just leave the series alone. But I am a completionist at heart and finally just buckled and bought this book. This one actually hangs together very well. VI is focused on figuring out how a daughter of one of Lotty's childhood playmates is doing after it looks like she may be in danger. The plot revolves around that, pre and post War World II, and the arms race. There were so many lines in this book that I found myself loving.

"Critical Mass" has a 50 year old or 50 plus year old VI off to help a childhood friend of Lotty's daughter. Lotty actually washed her hands of the friend and though she tried to help the daughter, eventually gave up on that too. When VI shows up at a meth house, she finds a man dead (the scene described is stomach turning) and realizes the woman is missing. From there VI finds out the woman's son is also now missing and huge tech giant is scared he has stolen their plans and is out there selling his secrets to the highest bidder.

VI does what she does best, asks questions, and goes investigating via libraries, the internet, and just using old fashioned intuition to put two and two together. She manages to once again find herself in a gun standoff (seriously that part is getting old) and once again has to deal with being so run down and tired but managing to push through. One wonders though when VI is going to just have to retire. I cannot see her still taking punches and getting shot in her 70s. It's already pushing realms of belief that she is able to walk after some of her run ins.

VI is still in a romance with Jake. I do like him and was surprised to see how well they mesh.

The secondary characters of Lotty and Max were welcomed. I was so glad to see Petra (VI's cousin) banished to the Peace Corps. I wish Mr. Contreas would go with Petra. I don't see how a guy pushing 90 is even doing running around with VI.

The writing was good and of course we get some historical facts mixed in to make this more realistic. I do love that Paretsky has made VI an unapologetic feminist and pushes for more individual rights over the government, cops, and anyone that could oppress them. Even though these are fictional characters, reading about what the fictional Nazis did to people during the Holocaust was awful.

The flow was actually pretty good in this one and I was able to follow the plot easily enough.

The setting of Chicago continues to surprise and Paretsky manages to make things fresh.

There were some surprises here and there and the ending was a surprise. We find out a lot of secrets that even the main participants in this one didn't know.